Development of a PGPB-based biofertilizer to optimize strawberry cultivation in semiarid regions: Screening, validation and scaling up to commercial production

The interest in the use of PGPR-based biofertilizers has increased in the last few years, since they may allow crops to increase their productivity through alleviating environmental stress. However, this promising technology is still at an early experimental stage since the majority of evidence has been obtained under controlled conditions. Therefore, the technology readiness levels (TRL) of PGPR-based biofertilizers is in low phases (1–4; laboratory environment), so it is necessary to focus on higher phases to achieve real implementation. In this study, our aim was to reach levels framed between TRLs 5–6, from relevant to the real environment, which addresses the design and development of a definitive prototype of PGPR-based biofertilizer to improve strawberry production under two agronomic managements [ FS1 (100 % application of evapotranspired water and conventional fertilizer application) and FS2 (70 % application of irrigation and fertilization reduction to 70 %)] through three experimental phases (1: biofertilizer screening; 2: validation under greenhouse; and 3: trial validation in a commercial strawberry production facility). Phases 1 and 2 allowed us to select biofertilizer 2 (PGP strains SDT3, HPJ40, SMT38, SRT15 and S110) which was able to increase production c. 13 % and 23 % under the FS1 and FS2 treatments, respectively. Furthermore, a significant relationship was also found between biofertilizer supply and the accumulation of primary metabolites. These positive effects were associated with the higher plant carbon assimilation capacity and photosystem energy efficiency. Commercial facility trial validation results showed an increase of 10 % and 8 % in inoculated plots with respect to non-inoculated plots under FS1 and FS2 treatments, respectively. Likewise, this positive effect was related to positive physiological responses. Although the biofertilizer effect was less acute than under laboratory conditions, the magnitude of the percentages obtained was important enough to validate the positive impact of biofertilizer 2 on strawberry yield in the real environment to be able to verify the development of this technology up to level 6.